It’s very simple, SF works like any other boost in the game. The amount of damage is based on base damage, and it’s piled on top of the total. For SF, that damage should be 150% of base, but seems bugged.

So if SF worked as planned, your damage for a dragon with base damage 100 (with boosts and rider) is:

That said, I do recognize that the math @Morreion ran matches my own, and this is a weird occurrence. For what it’s worth, I checked the parameters for the spell both on the release version that went live and in several future releases that haven’t gone out yet and they all point to a 150% boost from Scarlet Fever (meaning a 2.5 times multiplier). The parameter is correct ,but there may be another issue that we’re not currently aware of. This definitely deserves an investigation.

May I suggest that the spell might have a 100% cap just like Fury of the wastes (100) or War cry (200). It could be inherited from the code of a base spell on which all these spells are based. Basically you increase the damage to 250 but cap it at 200.

Is Sylphen even worth it? I have him at green and works like Hauheset, is he even in same league as prospero? sitting on 22k sigils and debating where to spend them.

Did you get Cavaleris, and are you trying to get Pathox? If Yes, finish Sylphen, get Pathox. If no - I have no idea why anyone would get Sylphen unless they fancied themselves as an “expert” flyer and wanted to make supercool videos to prove it.

I’ve wanted to like Sylphen all the way up through Emerald now, and I still just don’t.

i only use him on high level bases to setting up the killbase. usually takes my 3 dragons level 236 to take down a 300+ for their resources. But between, hauset, sylphen and one other dragon i can do it as long as there are no defenders LOL But as a solo 5 flame dragon it is tuff.

As an example, if Prospero has 8,000 base attack power, and his dragon rider increases his attack power to 9,000. The post-Scarlet Fever damage will be 20,000, not 22,500.

Shouldn’t that be 21.000 ?
Or does the rider buff completly disapaer ?

It should be 21,000 for the total, but he may intend to only show the difference in buff increase rather than the end result.

Because we use 250% instead 100% + 150%. (Increase is only 150%, but it gets added to the original amount) and because he was trying to show the difference between compounded vs additive bonuses, you need it broken before you can compare compound vs additive.